kingdom fungi continued....... fungal phyla 3 phyla but 4 groups: phylum zygomycota (zygomycetes or...
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Fungal Phyla• 3 phyla but 4 groups:• Phylum Zygomycota (zygomycetes or bread molds):
Meiospores made by zygosporangium (resistant microscopic structure).
• Phylum Ascomycota (ascomycetes or sac fungi): Meiospores made in sac-like ascus. Asci (plural) containing in fruiting body called ascoma (plural ascomata).
• Phylum Basidiomycota (basidiomycetes or club fungi): Meiospores made on club-like basidium. Basidia (plural) contained in fruiting body called basidioma (plural basidiomata).
Fungal Phyla• 3 phyla but 4 groups
• 4th group? Fungi that don’t make meiospores (to our knowledge)
• Called Imperfect Fungi
• Reproduce only asexually (by mitospores)
• Not a true phylum but a temporary holding group.
Fungal Phyla: Zygomycota• Zygosporangium is key
trait: often thick-walled and stress-resistant
• No dikaryotic hyphae: karyogamy followed by meiosis.
Zygosporangiaof 3 genera of zygomycetes
Zygosporangiumphoto
Fungal Phyla: Zygomycota• Make two types of spores:
– meiospores from zygosporangium– mitospores (asexual) from mitosporangia. These
help fungus to spread rapidly.
meiospores
mitospores
• Meiospores (called ascospores) made in ascus in ascoma (fruiting body)
• Dikaryotic hyphae and monokaryotic hyphae together form ascoma.
Ascoma
Fungal Phyla: Ascomycota• Mitospores often made by pinching off cells at tips of
hyphae. These called conidia. Each can start new mycelium.
Fungal Phyla: Ascomycota• Yeasts: an important group of (mostly) ascomycetes• Fermentation by yeasts useful for making alcoholic
beverages and in baking. Worth billions of dollars a year to industry.
Modern industrialwine-making
Fungal Phyla: Ascomycota• Yeasts: an important group of (mostly) ascomycetes• Some yeasts can cause disease: yeast infections and
others.
Yeast infectionbetween toes
Fungal Phyla: Ascomycota• Some ascomata are edible and highly
prized by gourmets• Truffles (worth up to $320/pound)• Morels
Morel
Trufflecut open
Pile oftruffles
Fungal Phyla: Basidiomycota• Meiospores made
on club-shaped basidium in basidioma (fruiting structure)
• Dikaryotic hyphae predominate in life of organism, and basidioma made only of these hyphae.
Fungal Phyla: Basidiomycota• Basidiomata
commonly observed.
A stinkhorn A shelf or bracket fungus
A jelly fungus
A mushroom
Fungal Phyla: Basidiomycota• Sexual reproduction: Usually do not make
mitospores, but mycelium can become fragmented to form separate individuals.
Fungal Phyla: Basidiomycota• Humongous fungus!• Largest organism on
planet? • Armillaria in National
Forest in Oregon reported to be 3.5 miles across, cover 2,200 acres. May be 2,400 yr old.
Fig. 36.6Aerial view of smaller forest patches infected by Armillariain Montana
Fungal Phyla: Basidiomycota• Importance:
– food (basidioma eaten, but beware of poisonous ones)
Amanita (death cap fungus:A poisonous basidioma
Fungal Phyla: Basidiomycota• Importance:
– pathogens of plants (smuts and rusts cause billions of dollars in damage to grain crops). Corn smut
Stemrustonwheat
Ergot on wheator rye
Ergotism, LSD, Salem witch trials
Fungal Groups: Fungi Imperfecti• Large group (17,000 species)
• Hyphae septate
• Reproduction asexual only, by conidia
• Most thought to be Ascomycota fungi, but until sexual reproduction observed we can’t be sure!
Fig. 36.12, showingconidia of severalgenera
Fungal Groups: Fungi Imperfecti• Importance
– decomposers– food rotters (can make toxins: aflatoxins in peanuts)– food production (flavor cheeses: Roquefort, Bleu
cheese)
Bleu cheese
Fungal Groups: Fungi Imperfecti• Importance
– produce antibiotics (ex, penicillin from Penicillium) and other drugs (cyclosporin)
Note inhibited growth of Staph bacterium near fungus colony
Fungal Groups: Fungi Imperfecti• Importance
– plant and animal diseases (human examples: athlete’s foot and ringworm)
Ringworm on leg
Athlete’s foot infections
Special Fungal Mutualisms• Mutualism: relationship between 2 species where both
benefit• Lichens: partnership between fungi and unicellular
photosynthesizer (green alga or cyanobacteria)
Fig. 36.13
Special Fungal Mutualisms• Fungus forms body and protects
and directs photosynthesizer, obtains materials from partner
• Together, can colonize harsh environments.
Fig. 36.14
Lichen Importance• Primary producers in
harsh environments (base of food chains)
• Ex, reindeer in arctic eat large amounts of lichens
• Some are pollution sensitive: used as bioindicators of air quality.
Special Fungal Mutualisms• Mycorrhizae: Association of fungus with plant root• Common: 90% of plants do this!• Mutualism: fungus extends into soil and aids in
uptake of nutrients (P, Zn, Cu in particular) for plant• Fungus obtains sugars from plant.
Special Fungal Mutualisms• Important in revegetation/reclamation of disturbed
areas: if fungi not present, plants don’t do well!.
Plant on left grownwithout mycorrhizal fungi
Special Fungal Mutualisms• Two types: endomycorrhizae in which fungus
penetrates root cells• Ectomycorrhizae in which fungus penetrates between
root cells.
Fig. 36.15aFig. 36.15b
Special Fungal Use: Biocontrol• Biocontrol: Using an organism’s natural enemies
against it• Some fungi attack insect pests• Some fungi capture and consume nematodes
(roundworms) that can cause agricultural problems.
Fly killed by fungusNematode predator fungus showing ring-like traps holding worm
Plants: Kingdom Plantae• Important:
– Vital for human food, medicines, clothing, building materials, etc.
Foxglove: source ofdigitalin (heart med.)
CornCotton
Lumber from trees
Plants: Kingdom Plantae• Important:
– Create much of the oxygen in atmosphere (and ozone!)
Aquatic plant makingoxygen bubblesduring photosynthesis
Oxygen and Ozone• Ozone is pollutant at Earth’s surface
• At outer atmosphere, oxygen gas produces ozone layer
• Vital, as it absorbs lots of ultraviolet (UV) radiation
• UV radiation damages DNA in skin cells
• Can cause skin cancer.
The Ozone Hole• Some pollutants damage ozone layer
• It’s getting thinner
• At South Pole, a hole has started to appear
• Getting larger.
The Ozone Hole• Some pollutants damage ozone layer (getting
thinner)• At South Pole, a “hole” has started to appear.
The Ozone Hole
• UV light is one cause of skin cancer
• Australia already has highest skin cancer rate on Earth.
Plants: General Features• Chemistry
– chlorophylls a + b, carotenoids (accessory pigments that aid photosynthesis)
– energy stored as starch
Plants: General Features• Chemistry
– review: starch and cellulose are both made of glucose.
Fig. 3.27
Plants: General Features• Water-saving features (most)
– cuticle: waxy layer on body surface– stomata: specialized cells that form pores in
surface (let CO2 in for photosynthesis, can close to prevent water loss when it’s dry)
Glowinglayer is cuticle
Plants: General Features• Water transport tissues: vascular tissues
– Xylem: dead cells that carry water. Walls rigid with lignin (reinforcing material, resists decomposition)
– Phloem: living cells that carry sugars.
Phloem tissue
Xylemtissue
Plants: General Features• Reproductive features
– Sporic meiosis (form gametophyte and sporophyte bodies)
– Gametes specialized (oogamy)• eggs: contain genes and stores materials (large)
• sperm: contain genes. Small to be mobile
– Gametangia specialized• made of many cells (multicellular)
• with outside layer of protective cells (sterile jacket)
Plants: General Features• Reproductive features
– Gametangia specialized• antheridium: gametangium that contains sperm
• archegonium: gametangium that contains an egg
ArchegoniumAntheridium
Plants: General Features• Reproductive features
– Egg fertilized in archegonium– Zygote starts to grow in archegonium
• embryo: young sporophyte retained and nourished by parent sporophyte
Young embryoin archegonium Older embryo
Plants: General Features• Reproductive features
– Make only meiospores (no mitospores for asexual reproduction)
– These made in meiosporangia (spore containers), called just sporangia because no mitospores made
– Inside meiosporangia, diploid cells called meiospore mother cells undergo meiosis to make meiospores (sometimes called just spores because no mitospores are made).
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